1. Field
The disclosed technology relates to a display device and a manufacturing method thereof with improved performance and low manufacturing complexity.
2. Description of the Related Technology
A thin film transistor (TFT) for a flat panel display device, such as a liquid crystal display element, an electroluminescence display element or an inorganic electroluminescent element, is used as a switching element to control the operation of each pixel and a driving element to drive pixels.
In general, a TFT includes source and drain regions that are highly doped with impurities, an active layer, a gate electrode, and source and drain electrodes. The gate electrode is positioned at a position corresponding to the channel region and the source and drain electrodes respectively contact the source and drain regions.
The active layer is formed of a semiconductor material, such as amorphous silicon or polysilicon, and has a channel region, which is formed between the source and drain regions.
When the active layer is formed of amorphous silicon, it usually is difficult to embody a high speed driving circuit because carrier mobility, the mobility of electrons and holes, is low. When the active layer is formed of polysilicon, an additional compensation circuit is needed because the carrier mobility can be high and a threshold voltage Vth is not uniform. Recently, research for using an oxide semiconductor as an active layer have been conducted in order to solve the problem described above.
An oxide TFT using the oxide semiconductor as the active layer is easily implemented and can have a large area when manufactured in a low temperature process. In addition, an oxide TFT has a very favorable electrical property like polysilicon.
The above information disclosed in this Background section is only for understanding of the invention. It may contain information that does not constitute prior art.